Large scale environments where real performance matters. I wrote a system the has to handle 4 Billion transactions a day and a peak of 45,000 per second. And

Large scale environments where real performance matters. I wrote a system the has to handle 4 Billion transactions a day and a peak of 45,000 per second. And has to respond in 10ms or else the results of the transaction are discarded. I wrote it in PHP so it would be easier for my team to maintain but it would not scale beyond 4,500qps then I re-wrote it in C as an apache module and it now scales to 25,000qps per server. Sometimes you just have to write stuff in C. I've been writing in C for 28 years. I write other languages as often as I can but once in a while I have to go back to C to get something done. Right tool for the right job!